Changeset 189

Timestamp:

02/16/10 19:38:16 (14 years ago)

Author:

oschonef

Message:

• try to running queries, if result set will be empty

Location:

VirtualCollectionRegistry/trunk/VirtualCollectionRegistry/src/main/java/eu/clarin/cmdi/virtualcollectionregistry

Files:

• VirtualCollectionRegistry.java (modified) (3 diffs)
• model/VirtualCollectionList.java (modified) (2 diffs)

VirtualCollectionRegistry/trunk/VirtualCollectionRegistry/src/main/java/eu/clarin/cmdi/virtualcollectionregistry/VirtualCollectionRegistry.java

@@ -267 +267 @@
                 try {
                         em.getTransaction().begin();
+
+                        List<VirtualCollection> results = null;
                         // FIXME: use TypedQuery variant when migrating to JPA 2.0
-                        long totalCount = 
-                                (Long) em.createNamedQuery("VirtualCollection.countAll")
-                                                        .getSingleResult();
-                        Query q = em.createNamedQuery("VirtualCollection.findAll");
-                        if (offset > 0) {
-                                q.setFirstResult(offset);
-                        }
-                        if (count > 0) {
-                                q.setMaxResults(count);
-                        }
-                        List<VirtualCollection> results =
-                                (List<VirtualCollection>) q.getResultList();
+                        Query cq = em.createNamedQuery("VirtualCollection.countAll");
+                        long totalCount = (Long) cq.getSingleResult();
+
+                        // optimization; don't query, if we won't get any results
+                        if ( totalCount > 0) {
+                                // FIXME: use TypedQuery variant when migrating to JPA 2.0
+                                Query q  = em.createNamedQuery("VirtualCollection.findAll");
+
+                                if (offset > 0) {
+                                        q.setFirstResult(offset);
+                                }
+                                if (count > 0) {
+                                        q.setMaxResults(count);
+                                }
+                                results = (List<VirtualCollection>) q.getResultList();
+                        }
                         return new VirtualCollectionList(results, offset, (int) totalCount);
                 } catch (Exception e) {
@@ -298 +304 @@
                 try {
                         em.getTransaction().begin();
+
                         User user = fetchUser(em, principal);
                         if (user == null) {
                                 throw new VirtualCollectionRegistryException("user does not exist");
                         }
+                        List<VirtualCollection> results = null;
 
                         // FIXME: use TypedQuery variant when migrating to JPA 2.0
-                        long totalCount = 
-                                (Long) em.createNamedQuery("VirtualCollection.countByOwner")
-                                        .setParameter("owner", user)
-                                        .getSingleResult();
-                        Query q = em.createNamedQuery("VirtualCollection.findByOwner");
-                        q.setParameter("owner", user);
-                        if (offset > 0) {
-                                q.setFirstResult(offset);
-                        }
-                        if (count > 0) {
-                                q.setMaxResults(count);
-                        }
-                        List<VirtualCollection> results =
-                                (List<VirtualCollection>) q.getResultList();
+                        Query cq = em.createNamedQuery("VirtualCollection.countByOwner");
+                        cq.setParameter("owner", user);
+                        long totalCount = (Long) cq.getSingleResult();
+
+                        // optimization; don't query, if we won't get any results
+                        if (totalCount > 0) {
+                                // FIXME: use TypedQuery variant when migrating to JPA 2.0
+                                Query q  = em.createNamedQuery("VirtualCollection.findByOwner");
+                                q.setParameter("owner", user);
+                        
+                                if (offset > 0) {
+                                        q.setFirstResult(offset);
+                                }
+                                if (count > 0) {
+                                        q.setMaxResults(count);
+                                }
+                                results = (List<VirtualCollection>) q.getResultList();
+                        }
                         return new VirtualCollectionList(results, offset, (int) totalCount);
                 } catch (VirtualCollectionRegistryException e) {
@@ -328 +340 @@
                 }
         }
-        
+
         private static User fetchUser(EntityManager em, Principal principal) {
                 User user = null;

VirtualCollectionRegistry/trunk/VirtualCollectionRegistry/src/main/java/eu/clarin/cmdi/virtualcollectionregistry/model/VirtualCollectionList.java

@@ -1 +1 @@
 package eu.clarin.cmdi.virtualcollectionregistry.model;
 
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
@@ -11 +12 @@
         public VirtualCollectionList(List<VirtualCollection> list, int offset,
                         int totalCount) {
-                this.collections = list;
+                if (list != null) {
+                        this.collections = list;
+                } else {
+                        this.collections = Collections.emptyList();
+                }
                 this.offset      = offset;
                 this.totalCount  = totalCount;